Process of concentrating solutions.



E. MONTI.

PROCESS OF GONOENTRATING SOLUTIONS.

APPLICATION FILED SEPT.9,1904.

Patented Apr. 27, 1909.

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PROCESS OF CONGENTRATING SOLUTIONS.

APPLIUATION FILED SEPT.9,1904. 919,61 6, Patented Apr. 27, 1909.

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Patented Apr. 27, 1909.

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B. MONTI.

PROCESS OF CONCENTRATING SOLUTIONS.

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v UNITED STATES PATENT OFFICE.

EUDO MONTI, OF TURIN, ITALY.

PROCESS OF CONGENTRATLNG SOLUTIONS.-

Specification of Letters Patent.

Patented April 27, 1909.

Application filed September 9, 1904. Serial No. 223,920.

ments in Processes for Concentrating Solutions, of which the following is a specification.

This invention relates toprocesses for conccntrating solutions and more particularly to an improvement for carrying on the rocess described in my Patent #761,387, ated May 31, 1904, in which the solutions or liquids, (any kind of animal, vegetable or fruit extracts, such as beet sugar,'meat, coffee,

tea, also mineralsolutions and the like) are frozen and the soluble matters are displaced from the ice.

In re eated experiments, I have'ascertained t -hat when freezing a solution in a mold or tank in order to concentrate it, much better results are obtained if the freezing is caused to proceed regularly from the top to the bottom of the material. I have also ascertained that the permeability of the frozen solution is an inverse ratio of the ercentage of ice crystals present in said so ution and the percentage of ice crystals, being the same, is an inverse ratio of the viscosity of the concentrated solution to be displaced from the ice crystals. I have further ascertained that the ermeability may be greatly increased and tiierefore the duration of the dis lacement shortened by saturating the coo ed solution to be frozen with air, dr carbonic acid or other suitable gas .whic 1 will not alter the solution. I have still further discovered that, it is greatly advantageous to stir the solution while the freezing is going on.

An a )paratus adapted for carrying out the above i'scoveries is illustrated in a division of an'application filed by me September 9,

1904, Serial No. 223,919, and to make my process clear I herein illustrate and describe Fig. 3 is a pump for forcing the liquid to trated or the displacing fluid from a suitable source of supply through pipe 3 into the spreaders 4 at the top of the freezin tank, and from here it asses into the sai tank. The tank is provi ed with an outlet pipe 11 having a perforated late 12covering its inner end, and leadmg to the displaced liquid tanks described in my previous patent and my application filed bcpteinber 9, 1905, Ser. No. 223919. Located within the tank are a number of superposed spiral coils 5 arranged in airs. The upper coil of each pair has an in ct pipe 6- at its outer end or circumference and is connected at its center with the center of the lower coil by a pipe 7, the outer end or circumference of the lower coil being connected to an outlet pipe 8. The inlet pipes of the several pairs are connected to pipes a, b, c, d and the outlet pipes are connected to pipes a, b, c, d, valves 9 and 10 respectively serving to control the flow through the inlet and the outlet pipes 6 and 8. Also located within the freezmg tank is a series of vertical pipes 13 which are connected together at their upper and at their lower ends, the inlet pipe 14 being connected to a valve. 15 in the pipe 3 whereby it be connected with the pump 2 and the may out et pipe 16 being connected to valve .17 in pipe 3, whereby it may be connected to the s readers 4. A pipe 18 is connected by a tiireewa valve 19 to the outlet pi e 11 and by a valve 20 with the pipe 3. xtendin within the tank, one for each pair of s ira coils, is a number of thermometers 21 w rich are connected with signal bells 22. Menometers 23 may be connected by valves 24, 25 with the inlets or the outlets of each pair of coils.

The 0 eration of the invention is as follows: T e solution to be concentrated is forced by pump 2 into the tank or mold 1 through pipe 3 and s readers 4. .A refriger. ant is then directed 'rom the pipe a into the upper pair of coils 5 until one of .the ingredients (such as water) of the solution in the upper part of the tank is crystallized or frozen. Some of the soluble matters in the be concenupper crystallized part of the tank then drop surrounding t e next pair of coils to a lower temperature. The most condensed matters ally more and more diluted solutions obtained fronr a previous operation, as described in my a ove mentioned patent, are successively forced by pump 2 through pipe 14 into the cooling pi es 13 and cooled to a tern erature slightly a ove the freezing point of t e crystallized ingredient. After which the cooled displacing fluid is conducted through pipe 16, valve 17 and pipe 3 to the spreaders' 4 from which it passes into the tank and displaces the gradually more and more dilute solutions.

The refrigerant employed is preferably a com ressed or liquefied gas previously cooled to a most 0 by circulating in the coils in the freezing tank when the ice separated in a revious operation is contained therein, thisli uefied gas being evaporated within the 00' s to produce the freezing. But of vcourse also cooled brine may be used.

Under ordinary circumstances, the pi we will become coated with hard inipermea lc ice thereby retarding the progress of the freezing and the displacement. This objection is overcome by the use of the independently controlled coils, by previously saturating with air, dry carbonic acid or other suitable gas the solution-to be frozen, and by stirring the solution while the freezing is going on, preferably byinjecting gas therein also by running lukewarm brine through the coils after the freezing is over.

I This also enables me to extract a higher percentage of Water. The gas is conducted from the pipe 18 and through pipes 11 or 3 to the freezing tank. The gas em iloyed for saturating or.- stirring the liquid should not contain any active oxy en so as to prevent the oxidation of the so ution to be concentrated and the alteration of its taste. This gas or a li uid under pressure, may be employed to asten the displacement of the concentrated solution interposed between the'ice crystals, but the pressure should be so regulated that the displacement does not proceed too quickly in order to allow the concentrated solution time to diffuse in the displacing solution.

At the first operation and all future operations, if desired, after the most concentrated matter has been forced out or drained off, the refrigerant, in a Warm state, is first directed through the upper coils, thereby causing a melting'of the frozen mass in the upper part of the tank. This melted matter then displaces the soluble matter still held within the crystals of the frozen mass below, producing a more dilute solution than the most concentrated solution. The warm fluid is then directed through the next coil and so on until the whole frozen mass has disappeared and the resultant has been drained from the tank, thus producing first gradually more and more diluted solutions and pure water afterward. These gradually more and more dilute solutions may be used to displace the soluble matters held within the frozen mass of another operation, or they may be again frozen and have their remaining soluble matters displaced by the above mentioned process. By melti v the ice within the tank the concentrated so ution is not exposed to impure air and the labor of manually remov ing the ice from the tank is saved.

The invention has enabled me to displace the interposed concentrate solutions from solutions frozen at temperatures ranging from3t t0-6t (I! being the freezing point vof the solution in degrees oentigrades below the freezing point of water).

Said temperature expressed in absolute degrees would range from 273-3 (273-T) to 273 -6 (273 T), (T being the absolute temperature at which the original solution starts to freeze, expressed in degree centigrade) according to the viscosity of the concentrated solution, and provided that the freezing point of the saturated solution is not passed.

The interposition of coils in the frozen solution does not interfere with the displacement provided that they are evenly distributed and that the freezing is carried on slowly and skilfully in order to prevent any part of the solution becoming cooled to a temperature-at which the frozen mass would be impermeable.

This process is adapted for use in concentrating musts, drugs or other vegetable or mineral extracts, coffee, tea and meat extracts'and the like.

Lemon juice and the like ought to be concentrated in aluminum, lead or glass coated, cement or masonry tanks, also in tanks silvered or coated with a special paint. The coils should also be coated with lead, paint or enamel.

With the exception of some strong liquorous wines, such as Madeira, Malaga, port and the like, which'have their taste improved if a stream of air is caused to dissolve into the freezing liquid, the concentration of wine and fruit juices should always take place in an atmosphere of dry carbonic acid or other inert or reducing gas and the diluted displacing solutions should be stored in a refrigerated room. Beer also being very easily altered should never be allowed to warm or come into contact with air.

Meat juice should not only be concentrated out of contact with active oxygen but the whole operation should be earned on in a ventlon may be carried out.

and filtered, once through a sieve to separate the grease and ther through another filter like under strong dry carbonic acid pressure to separate the germs. After this about 9/10 of the water may be separated by freezin according to the above process and the other tenth may be removed by evaporation in vacuum at a temperature not over ("10 C. and in an atmosphere of dry carbonic acid. The extract of meat thus prepared has a delicious flavor and contains many very Sui.- stantial ingredients which are lost or altered by the usual process.

In concentrating alcohol, glycerin, strong brine solutions and other solutions having their freezing points many degrees lelow the freezing point of water, the displacing solutions should be cooled by an independent refrigerating apparatus.

Referring to Fig. 3 which illustrates another apparatus for carrying out my process, 1 indicates the tank having mounted therein the independently controllalf-le coils 5 being arranged in pairs as in the first emlvodiment, the connecting pipes 7 a being deflected outwardly and connected to the circumference of the lower-coil instead of the center while the outlet 8 is connected to the center of the lower coil, thereby permitting the use of a stirrer or agitator. This stirrer c0mprises a vertical shaft 27 and horizontal arms 28 positioned between the coils and is turned l-y a shaft connected to the shaft 27 by gearing 30. The stirrer acts to agitate the solutron during freezing and prevent the uneven freezing of the mass. When other more economical means are not advisal'le I have shown for the sake of simplicity two pairs of coils connected to the pipes (1, a, d, d. In this apparatus, the coils are mnploycd not only for the refrigerant but for cooling the solution to be frozen and the displacing solutions. For this purpose pipes 14* and 16. connect the pipe 3 with the pipes a, a, d and (1 whereby through valves 15 and 17*, and valves 26, the solutions may he directed from the pump 2 into the coils 5 and back through the pipe 3 to the freezing tank. The operation is otherwise the same as that set forth in the description of the other embodiment.

In Fig. 4 I have shown diagrammatically a complete beet sugar factory in which my in- The defecated sugarjuice, obtained by the diffusion process generally in use, drips from the press filters 41 at a temperature of about 60 C. and has an average density of 1.05.0 corresponding to 10% weight of sugar, that is 11 weights of sugar in one hundred water. Its, freezing point should be 00.059 11 =0.65 C. beow zero if the'juice were pure. In fact however, the juice contains other substances which lower its freeziiu point to about -.0.80 or 272.2 absolute cgrees. With my by pump 42, the warm juice into the inter-' changers 43, where it is cooled by a suitable quantity of cooling water, and through pipe 44 and 11 to the freezing tank l where it IS frozen at a temperature not below 270.6 absolute degrees centigrade, by evaporating, in the upper coils first and the other coils afterward, liquefied gas coming from the condenser 45 through pipes 46 and 517, regulating valve 48 and pipes 49, a and d, returning through pip'es a, d, 50 to gas compressor 51. While the freezing is going on in tank 1 I fill tank 1 with a supply of cool juice from the inter-changers 43.. As soon as tank A has reached the required temperature I open cock orf valve 52 and allow the most concentrated hquor flowing from the frozen mass to descend through pipe 11 to the reconcentrating tank 1 When the concentrated solution has almost ceased to flow from the ice crystals, I cause the liquefied but still warm gas, coming from the condenser to circulate through the upper coils in tank 1, without passing the gas through the pressure regu latingvalve 48. The luke warm gas melts the ice crystals at the upper end of the tank, andthis melted ice strains through the ice crystals filling the lower end of the tank, displacess th'e concentrated juice interposed amidst said crystals and causes concentrated juice first and gradually more and more diuted sugary solutions afterward, to flow through pipe 11 into tank 1. When the flowin liquid is weaker than the original juice, cause the more and more diluted solutions drip )ing from the ice to fill reservoirs 53, and w en almost pure water flows I cireulate the warm compressed gas in the lower coils of the freezing tank, "thus melting the remaining ice. This ice cold water is lead through pipe 54 to the surface condenser 55 of the steam engine or to the jacket of a gas engine, to become heated. The water is then filtered,'in filters 56, and is used in diffusers 57 to displace the sugar from another sup ly of beets. If the juice has been previous y saturated with CO, under pressure the displacement is much quicker and easier and the separated ice quite pure. Meanwhile tl e solution in tank 1" has been frozen and tank 1 has been filled. instead of melting the ice in tank l displace, as usual, the concentrated solution with the more and more diluted solutions obtained in the operation of tank 1, cooling if necessary said solutions in a coil of tank 1", and make use of the dcp-uratcd ice crystals filling tank 1 to cool the displacing weak solutions to be strained through the ice se )arated in tank 1, also to cool the second solution to be frozen in tank 1 and the liquefied gas to be evaporated in order to freeze said solution. and so on for an ii'S unlimited number of operations. The reconcentration of the concentrated solution filling the tanks 1, 1 and 1 is carried on in the same way as the first concentration, the only difference being that said solution having a density of about 1.110 and containing I 25% sugar, that is 33 weight sugar in 100 water, its freezing point 2 degrees centigrade below zero (27 absolute degrees) and may be cooled to about 267 absolute degrees (6).

The reconcentrated solution containingabout 50% sugar (100 weight sugar in 100 water), after having been conducted by pipes 4 to the interchanger 43 and heated by the hot juice dripping from the press filters 41,is pum ed a vacuum concentrator 58 where it is-wor ed in the usual way in order to obtain crystallized sugar. If thequantity of sugar juice to be concentrated is very large, it is advisable to employ an additional compressor 51 with its condenser 45 and regulating valve 48. The sugar juice concentrated by freezing, not having been subjected to a high temperature, will give a higher percentage of crystallized sugar of a lighter shade than if concentrated in the usual Way.

Having described my invention what I claimas new, is:

1. The process of concentrating solutions which consists in freezing the upper portion of the liquid first to crystallize one of the ingredients thereof, freezing the liquid below the upper frozen portion at a temperature lower than the temperature-of the upper portion, and displacing the ingredients interposed amidst the frozen crystals.

2. The process of concentrating solutions which consists in saturating the solution with gas having no chemical action on the solution, freezing the saturated solution to 'crystallize one of the ingredients thereof, and removing the other ingredients from amidst the frozen crystals.

3. The process of concentrating solutions which consists in freezing thesolution to crystallize one of the ingredients thereof, injecting a gas into the solution durin the freezing, and displacing the other ingre ients from amidst the crystals.

4. The process of concentrating solutions which consists in freezin an ingredient of the liquid in layers beginning at the top, and

removing the other ingredients from amidst the frozen mass.

5. The process of concentrating solutions which consists infreezing the liquid to crystallize one ingredient thereof, displacing the other ingredient from amidst the or stals, by a liquid under pressure, and in regu ating the and then in displacing the concentrated matter by a displacing fluid.

8. The process of concentrating solutions which consists in freezing portions of the solution, in introducing a displacing .li uid 2 above the frozen mass, and then in intro ucing an inert gas under pressure above said displacing liquid in such manner as to cause the concentrated portions to be displaced downwardly.

9. The-process of concentrating solutions which consists in freezing ortions of the solution in a tank to crysta ize one of the ingredients thereof, next in dis lacing the other ingredients by the intro notion of a displacing fluid above the frozen portions to displace the concentrated matter downwardly, and lastly, in'rnelting the frozen portions by successive layers downwardly to provide periodic and additional supplies of displacing fluid.

10. The process of concentrating solutions which consists in freezing a solution in a tank to crystallize one ingredient thereof, next in coolin a fluid by the frozen mass thus forme then in dis lacing the other ingredients by the cooled uid, and lastly in melting the frozen mass within the tank to provide additional displacin fluid.

11. The process 0 concentrating solutions which-consists in freezing portions of the solution,'in introducingra diluted portion of the solution above the ozen mass, then in introducing a gas, free from active oxygen and under pressure, above said diluted solution, and finall 1n varying the pressure under Which-sai inert gas is introduced above the dilute solution, whereby a maximum degree;

of efliciency is attained in the downward dis-.

placement of the concentrated portions.

The foregoing specification signed at Turin,

EUDO MONTI. In the presence of two witnesses: GOTTARDO C. PIRONI, C. GrAoHE'rTI.

. Piedmont, Italy. 

